Self-propelled machines, such as lawn mowing machines or lawnmowers, are often powered by a gasoline engine and can have a self-propelled drive system that moves the lawnmower forward under its own power. Conventional “walk-behind” types of self-propelled lawnmowers typically use a drive system that is mechanically coupled with the engine crankshaft. Typically, a transmission converts the speed and direction of rotation of the engine to transmit power to the lawnmower wheels. In such a configuration, the transmission can have either a variable speed output or a fixed speed output. However, when an operator encounters very tall grass during operation of the self-propelled lawnmower, there is a likelihood of engine stall due to the increased load on the engine. Currently, in such scenarios, self-propelled lawnmowers require the operator to either reduce the transmission speed or disengage the transmission drive to reduce the load on the engine and prevent the engine from stalling. In order for the operator to perceive that the engine is experiencing a load that may cause it to stall, the operator must rely on the sound of the engine.
Therefore, a need exists for engine stall protection in conventional, self-propelled “walk-behind” lawnmowers that are time-efficient, and simple and easy to use, in order to allow the operator to focus only on mowing without concern about engine stall.